2005+ Mustang GT question on spark plugs - Ford Mustang Forum
 
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post #1 of 7 (permalink) Old 04-16-2008 Thread Starter
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2005+ Mustang GT question on spark plugs

Like the title says. While my car is not running bad I can't help feeling that something is not right. My mpg sucks. I only have 12k, am running a moderate tune and while I drive aggressively at times I am not a maniac and am only getting 15 or so. I have read that fouled plugs can cause this issue. I haven't pulled them yet but will this weekend so I thought I would ask what I should look for.

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2007 Mustang GT California Special. Redfire with black/parchment leather, 5 speed. K&N Aircharger, Hood Struts, Custom Painted Gril Pony, SHR Sequential Tail Lights, SHR Honeycomb Taillight Panel, SHR Lower Grill Insert, BMR Strut Tower Brace, MGW Shifter @ 5 turns, GT500 Rear Splash Guards, Clear front markers w/stealth bulbs, SHR Flush-Mount louvers,MAG Mirror Covers, Ford Racing GTAs, painted brake calipers
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post #2 of 7 (permalink) Old 04-16-2008
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15,18 about right for agressive driving. 12-15 about right for maniac driving! 20,25 for slow cruising 25-30 for driving a nonmustang auto!


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post #3 of 7 (permalink) Old 04-16-2008
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Here's a very good tool.
Interpreting your spark plugs

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post #4 of 7 (permalink) Old 04-16-2008
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Quote:
Originally Posted by stlwagon View Post
Here's a very good tool.
Interpreting your spark plugs
If your plugs look like any of those you'd be getting way less than 15 mpg.

2005 Mustang GT with 300 ci 04 Cobra iron block, Kenne Bell 2.6l twin screw, P&P S3 Heads, SS valves, Comp S3 cams, Currie 9+ 9" rear end and DS, Hurst shifter, BMR K-member, A-arms, LCAs & UCA, JBA long tubes & mid-pipe, Accel COPs, Dual GT500 fuel pumps, much more...
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post #5 of 7 (permalink) Old 04-16-2008 Thread Starter
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Thanks guys!
On the page STL linked it said that 10-12k of normal use the plus should be replaced. Is that still true for our plugs?

2007 Mustang GT California Special. Redfire with black/parchment leather, 5 speed. K&N Aircharger, Hood Struts, Custom Painted Gril Pony, SHR Sequential Tail Lights, SHR Honeycomb Taillight Panel, SHR Lower Grill Insert, BMR Strut Tower Brace, MGW Shifter @ 5 turns, GT500 Rear Splash Guards, Clear front markers w/stealth bulbs, SHR Flush-Mount louvers,MAG Mirror Covers, Ford Racing GTAs, painted brake calipers
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post #6 of 7 (permalink) Old 04-17-2008
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Quote:
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Thanks guys!
On the page STL linked it said that 10-12k of normal use the plus should be replaced. Is that still true for our plugs?
No... Our plugs are designed to last a lot longer than that.

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post #7 of 7 (permalink) Old 04-17-2008
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Service manual calls for replacing at 100,000 miles.

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